Relativistic Traveling Wave Amplifier Based on Two Electron Beams

In general, HPM systems currently being developed use oscillators as their RF source. These systems operate at a fixed frequency and are not readily tunable. In contrast to oscillators, a broadband amplifier has the frequency agility necessary to maximize electromagnetic (EM) coupling into targeted electronics. The multiple beams traveling wave tube amplifier (TWTA) technology can enhance the bandwidth of the TWTA and lead to superexponential growth. 1 , 2 In coupled cavity TWTs, several tens of klystron-like cavities are used as the slow wave structure, which are coupled for RF signal propagation. 3 The coupled cavity approach with shallow corrugations results in a wider bandwidth. However, its bandwidth is still a fraction of the bandwidth of the helix- TWT which is a relatively low power amplifier. In this work, two-stream technology is incorporated with a smooth-wall interaction region in order to enhance the bandwidth at the relativistic regime of operation. Input/output microwave coupling is an important factor for an efficient operation. The first stage of the study is to design an input coupler that is compatible with the two electron beams diode. This design is studied using MAGIC PIC simulations.